| Jtbdeliveries Ltd | Transport & logistics | 2025 |
| JTE Electrical Engineering Ltd | Construction | 2022 |
| JTI Properties Ltd | Real estate | 2018 |
| JTM Advance Ltd | Construction | 2026 |
| JTR Electrical Services Ltd | Construction | 2026 |
| Jucabelle Ltd | Wholesale & retail | 2025 |
| Julie Vevers Limited | Wholesale & retail | 2001 |
| Junction 45 Ltd | Wholesale & retail | 2019 |
| Just Accountancy Ltd | Professional & scientific | 2013 |
| Just E-Juice Limited | Wholesale & retail | 2015 |
| Just in Time Care Ltd | Health & social care | 2022 |
| Just Messin Ltd | Health & social care | 2020 |
| Just R Limited | Professional & scientific | 2013 |
| Justicetown A.D. Limited | Water & waste | 2013 |
| Justicetown Farm Limited | Agriculture & fishing | 2010 |
| JW LEE Pharma Ltd | Wholesale & retail | 2022 |
| JW Taxi Cumbria Limited | Transport & logistics | 2021 |
| JW Whitening Limited | Other services | 2025 |
| JWA Contractors Limited | Agriculture & fishing | 2026 |
| Jwac Services Ltd | Real estate | 2008 |
| JWP Farming Limited | Other services | 2021 |
| JWS88 Limited | Real estate | 2023 |
| JWT Solutions Limited | Professional & scientific | 2010 |
| K & D Rail Ltd | Professional & scientific | 2015 |
| K & R Foster Limited | Agriculture & fishing | 2004 |
| K 1 Engineering Services Limited | Manufacturing | 2014 |
| K C Irving Limited | Administrative & support | 1999 |
| K Design Limited | Professional & scientific | 2014 |
| K J & C S Wilson (Holdings) Limited | Agriculture & fishing | 2007 |
| K J & C S Wilson Limited | Agriculture & fishing | 2021 |
| K J Bell Electrical Limited | Construction | 2006 |
| K J P Holdings Limited | Professional & scientific | 2023 |
| K M a Partners Limited | Professional & scientific | 2011 |
| K&H Law Ltd | Professional & scientific | 2003 |
| K&K Homes Ltd | Real estate | 2025 |
| K&M Consultants Limited | Construction | 2024 |
| K&Tpubs Ltd | Hospitality | 2024 |
| K-Tec Systems Ltd | Wholesale & retail | 2021 |
| K. and T. Bodyshop Limited | Wholesale & retail | 2005 |
| K.& S.Mckenzie Limited | Wholesale & retail | 1971 |
| K.C.R. Properties (Cumbria) Limited | Real estate | 2025 |
| K.M.C. Industrials Limited | Manufacturing | 1989 |
| K2 Painting & Roofing Limited | Construction | 2019 |
| Kaars Flooring and Fitout Limited | Construction | 2025 |
| Kaizen Innovations Limited | Professional & scientific | 1999 |
| Kama Management Ltd | Real estate | 2021 |
| Kamansle Ltd | Wholesale & retail | 2026 |
| Kambel Healthcare Ltd | Health & social care | 2024 |
| Karen Mcgahon's Beauty Therapy Limited | Other services | 2015 |
| Karen Stuart EAR Care Ltd | Health & social care | 2025 |
| Karrma Ltd | Wholesale & retail | 2012 |
| Kasu Carlisle Ltd | Hospitality | 2024 |
| Kate Wright Digital Limited | Information & communication | 2019 |
| Kaths Curtains Ltd | Extraterritorial | 2018 |
| Katie Lewis Collective Ltd | Other services | 2026 |
| KAY Fast Food Limited | Hospitality | 2024 |
| Kayanis Food Ltd | Hospitality | 2025 |
| Kaz's Fade Ltd | Other services | 2025 |
| Kazer Systems Ltd | Information & communication | 2007 |
| KB Installations Ltd | Construction | 2002 |
| KB Landscaping and Groundworks Limited | Administrative & support | 2023 |
| KC Consultants (Cumbria) Ltd | Administrative & support | 2021 |
| KC Paws Ltd | Wholesale & retail | 2023 |
| KC Superbikes Limited | Wholesale & retail | 1978 |
| KCN Skincare Limited | Wholesale & retail | 2009 |
| Keelan Electrical Services Ltd | Construction | 2022 |
| Keep IT Simple (Sales & Marketing) Solutions Ltd | Extraterritorial | 2015 |
| Keith Davidson Roofing Limited | Construction | 2006 |
| Keith Mason Agricultural Engineer Limited | Manufacturing | 2002 |
| Keith Shackleton Associates Limited | Professional & scientific | 1968 |
| Kelmecor Limited | Health & social care | 2019 |
| Kels Kitchen Ltd | Hospitality | 2025 |
| Kelsey Rose Aesthetics Ltd | Other services | 2023 |
| Kelsey Rose Properties Ltd | Real estate | 2024 |
| Kelsick House (AD) Limited | Energy | 2013 |
| Kelsick House Farm Limited | Agriculture & fishing | 2012 |
| Kemi Ayangade Films (KAF) Limited | Professional & scientific | 2025 |
| Kensley Properties Limited | Hospitality | 2016 |
| Kerrera (Cumbria) Ltd | Hospitality | 2019 |
| Kerverus Safety Ltd | Professional & scientific | 2010 |
| Keswick Outside Caterers Limited | Hospitality | 1999 |
| Keswick Property One Limited | Construction | 2026 |
| Keswickclub Ltd | Hospitality | 2025 |
| Kevin Bell (2006) Limited | Construction | 2006 |
| Key Compass Games Ltd | Information & communication | 2026 |
| Key Organs (Carlisle) Limited | Wholesale & retail | 2025 |
| Keyishoes Limited | Extraterritorial | 2010 |
| KF Account Services Limited | Professional & scientific | 2013 |
| KFS Rental Properties Ltd | Real estate | 2024 |
| KG Bricklayers Ltd | Construction | 2018 |
| KG Properties Cumbria Ltd | Real estate | 2022 |
| Khan Property Solutions Ltd | Real estate | 2023 |
| Khan's at the Waterloo Ltd | Hospitality | 2018 |
| Kibby Productions Limited | Information & communication | 2023 |
| KIE3D Limited | Professional & scientific | 2017 |
| Kierweb Limited | Information & communication | 2018 |
| Kifty Limited | Health & social care | 2021 |
| Kilncroft Management Company (Carlisle) Limited | Real estate | 2005 |
| Kilshaw Project Solutions Limited | Professional & scientific | 2019 |
| KIM Atkinson Property Ltd | Real estate | 2025 |